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Gravitational Field as a Pressure Force from Logarithmic Lagrangians and Non-Standard Hamiltonians：The Case of Stellar Halo of Milky Way

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Communications in Theoretical Physics 2018年第3期69卷 233-240页

作者： rami ahmad el-nabulsi Athens Institute for Education and Research Mathematics and Physics Divisions 8 Valaoritou Street Kolonaki 10671 Athens Greece

Recently,the notion of non-standard Lagrangians was discussed widely in literature in an attempt to explore the inverse variational problem of nonlinear differential *** forms of non-standard Lagrangians were introduced in literature and have revealed nice mathematical and physical *** interesting form related to the inverse variational problem is the logarithmic Lagrangian,which has a number of motivating features related to the Li′enard-type and Emden nonlinear differential *** types of Lagrangians lead to nonlinear dynamics based on non-standard *** this communication,we show that some new dynamical properties are obtained in stellar dynamics if standard Lagrangians are replaced by Logarithmic Lagrangians and their corresponding non-standard *** interesting consequence concerns the emergence of an extra pressure term,which is related to the gravitational field suggesting that gravitation may act as a pressure in a strong gravitational *** case of the stellar halo of the Milky Way is considered.

关键词：非标准对数 Lagrangian 重力压力盒子光圈银河

Accelerated Dilatonic-Brans-Dicke cyclic and non-singular universe from string theory

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Research in Astronomy and Astrophysics 2011年第11期11卷 1249-1256页

作者： ahmad rami el-nabulsi Department of Nuclear Engineering Cheju National UniversityAra-dong 1Jeju 690-756South Korea Key Laboratory of Numerical Simulation of Sichuan Province College of Mathematics and Information Science Neijiang Normal University

We discuss the late-time dynamics of a particular four-dimensional Brans-Dicke cosmology with a dilaton field motivated by string theories （solitonic p-branes or D-branes） in which the dilaton field and the scale factor of the fiat, homogeneous spacetime are correlated. We examine the late-time-evolution of the equations of motion where various attractive consequences are revealed artd discussed in some detail.

关键词： cosmology: theory-cosmological parameters

Dark energy in five-dimensional Brans-Dicke cosmology with dimensional reduction

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Research in Astronomy and Astrophysics 2011年第8期11卷 888-894页

作者： ahmad rami el-nabulsi Department of Nuclear Engineering Cheju National University South Korea College of Mathematics and Information Sciences Neijiang Normal University

We explore a 5D Brans-Dicke scalar cosmology by conjecturing that the four-dimensional Hubble parameter varies as H = εФ^s, ε ∈ R and s is some unknown power index and that the extra-dimensions compactify as the visible dimensions expand as b（t） ≈ a^x （t）, x ∈R^-. We mainly discuss the case x = - 1. For critical values of e close to unity, it was observed that the acceleration of the universe occurs at red- shift close to z = 0.8 which indicates that in our model, accelerated expansion of the universe began only recently. Several interesting points are revealed and discussed in some detail.

关键词： Brans-Dicke cosmology -- dark energy

Scalar Tensor Cosmology With Kinetic, Gauss-Bonnet and Nonminimal Derivative Couplings and Supersymmetric Loop Corrected Potential

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Communications in Theoretical Physics 2019年第7期71卷 831-836页

作者： rami ahmad el-nabulsi Athens Institute for Education and Research Mathematics and Physics Divisions8 Valaoritou StreetKolonaki 10671 AthensGreece

We discuss a particular four-dimensional cosmology based on non-minimal scalar tensor theories characterized by a supersymmetric loop corrected potential and a Hubble parameter defined as a function of the scalar ***-law solutions are obtained in the FRW background giving rise to acceleratedly expanding universe characterized by a scale factor and a scalar field depending both on the non-minimal coupling parameterξ.Based on SNeIa data and on Hubble data X-ray gas mass fraction measurements,we find 0.116<ξ<0.225 which results on a universe dominated by vacuum energy.

关键词： scalar tensor cosmology Gauss-Bonnet coupling non-minimal derivative coupling vacuum energy

New Metrics from a Fractional Gravitational Field

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Communications in Theoretical Physics 2017年第9期67卷 309-312页

作者： rami ahmad el-nabulsi Athens Institute for Education and Research Mathematics and Physics Divisions

Agop et al. proved in Commun. Theor. Phys.(2008) that, a Reissner–Nordstrom type metric is obtained,if gauge gravitational field in a fractal spacetime is constructed by means of concepts of scale relativity. We prove in this short communication that similar result is obtained if gravity in D-spacetime dimensions is fractionalized by means of the Glaeske–Kilbas–Saigo fractional. Besides, non-singular gravitational fields are obtained without using *** present few examples to show that these gravitational fields hold a number of motivating features in spacetime physics.

关键词：引力场度量分数尺度相关性分形测量非奇异物理学证明

Oscillating gravity,non-singularity and mass quantization from Moffat stochastic gravity arguments

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Communications in Theoretical Physics 2022年第10期74卷 110-115页

作者： rami ahmad el-nabulsi Waranont Anukool Center of Excellence in Quantum Technology Faculty of EngineeringChiang Mai UniversityChiang Mai 50200Thailand Quantum-Atom Optics Laboratory and Research Center for Quantum Technology Faculty of ScienceChiang Mai UniversityChiang Mai50200Thailand Department of Physics and Materials Science Faculty of ScienceChiang Mai University50200Thailand

In Moffat stochastic gravity arguments, the spacetime geometry is assumed to be a fluctuating background and the gravitational constant is a control parameter due to the presence of a timedependent Gaussian white noise ξ(t). In such a surrounding, both the singularities of gravitational collapse and the Big Bang have a zero probability of occurring. In this communication, we generalize Moffat’s arguments by adding a random temporal tiny variable for a smoothing purpose and creating a white Gaussian noise process with a short correlation time. The Universe accordingly is found to be non-singular and is dominated by an oscillating gravity. A connection with a quantum oscillator was established and analyzed. Surprisingly, the Hubble mass which emerges in extended supergravity may be quantized.

关键词： Moffat stochastic gravity Gaussian white noise oscillating gravity non-singular Universe mass quantization

Orbital dynamics satisfying the 4^(th)-order stationary extended Fisher-Kolmogorov equation

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Astrodynamics 2020年第1期4卷 31-39页

作者： rami ahmad el-nabulsi Mathematics and Physics Divisions Athens Institute for Education and Research8 Valaoritou StreetKolonaki10671AthensGreece

In this study,we discuss the central force problem by using the nonlocal-in-time kinetic energy *** low length scales,the system is dominated by the generalized 4^(th)-order extended Fisher-Kolmogorov stationary equation and by the 4^(th)-order stationary Swift-Hohenberg differential equation under explicit *** energy is a conserved quantity along orbits of the extended Fisher-Kolmogorov stationary *** system is quantized,the system is stable,and the ground energy problem is solved.

关键词： nonlocal-in-time kinetic energy 4^(th)-order differential equations quantization complex-shift method

Generalized heat diffusion equations with variable coefficients and their fractalization from the Black-Scholes equation

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Communications in Theoretical Physics 2021年第5期73卷 10-17页

作者： rami ahmad EI-nabulsi Alireza Khalili Golmankhaneh Biomedical Device Innovation Center Shenzhen Technology University3002 Lantian RoadPingshan DistrictShenzhen518118China Research Center for Quantum Technology Faculty of ScienceChiang Mai UniversityChiang Mai50200Thailand Athens Institute for Education and Research Mathematics and Physics Divisions8 Valaoritou StreetKolonaki10671AthensGreece Department of Physics Urmia BranchIslamic Azad UniversityUrmiaIran

In this study,we prove that modified diffusion equations,including the generalized Burgers'equation with variable coefficients,can be derived from the Black-Scholes equation with a time-dependent parameter based on the propagator method known in quantum and statistical *** extension for the case of a local fractal derivative is also addressed and analyzed.

关键词： Black-Scholes equation heat kernels modified diffusion equations generalized Burger's equation fractal calculus

Dark energy from logarithmically modified gravity and deformed Coleman-Weinberg potential

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Research in Astronomy and Astrophysics 2011年第7期11卷 759-766页

作者： ahmad rami el-nabulsi Department of Nuclear and Energy Engineering Cheju National University College of Mathematics and Information Sciences Neijiang Normal University

Recent astrophysical measurements strongly suggest the existence of a missing energy component dubbed dark energy that is responsible for the current accelerated expansion of the universe.A new class of modified gravity theory is introduced which yields a universe accelerating in time and dominated by dark *** new modified gravity model constructed here concurrently includes a Gauss-Bonnet invariant term,barotropic fluid with a time-dependent equation of state parameter,a Coleman-Weinberg（CW） potential-like expression V（φ） =ξφm lnφn and a new Einstein-Hilbert term f（R,φ） =E（φ） R which depends on both the scalar curvature and the scalar fieldφthrough a generic logarithmic function E（φ） =lnφ.Here m and n take different values from the standard CW potential andξis a real parameter. It was shown that the presence of these terms provides many useful features which are discussed in some detail.

关键词： dark energy—gravitation—equation of state